The myocardial response to behaviorally conditioned pressor responses will be investigated in intact, unanesthetized baboons to determine the effect of such events upon isolated segments of cardiac muscle during control vs acute periods of left anterior descending coronary artery occlusion. The increases in blood pressure will be elicited using a classical appetitive conditioning paradigm. Changes in muscle segment length will be assessed in normally oxygenated, marginally oxygenated and ischemic portions of the myocardium using ultra-sound techniques. Acute periods of myocardial ischemia will be produced by temporarily inflating a pneumatic occluder placed around the left anterior descending coronary artery. The behavioral conditioning trials will be conducted during control periods as well as during five minute long occlusions of the coronary vessel. Changes in coronary vascular resistance during classical appetitive conditioning will also be studied in dogs using ultra-sound flow probes to measure left circumflex coronary blood flow. Alpha adrenergic blocking agents will be used to assess the involvement of neurally induced vasoconstriction during behavioral conditioning in dog.